03 Feb Stratatech genetically modifies skin substitute
Madison, Wis. – Stratatech Corp., a privately-held regenerative medicine company, today announced that it has genetically modified its StrataGraft living human skin substitute to actively fight costly bacterial infections that routinely develop at the site of burns and other severe skin injuries, such as skin ulcers.
Bacterial infection is a primary cause of skin graft rejection and can significantly increase the hospital costs of burn and other skin injury patients. Stratatech’s skin-substitute innovation, detailed in an article published online this morning by the journal Molecular Therapy, enables the immediate topical delivery of a potent anti-infective that actively inhibits bacterial growth and promotes regrowth of the patient’s own cells.
Stratatech’s genetically-engineered skin substitute was generated using a non-viral vector, or carrier. The company believes it is the first time a virus-free approach has been used to genetically modify a living, cell-based tissue substitute. The data published in Molecular Therapy demonstrate that the modified tissue contained 139-fold more anti-infective proteins called host defense peptides than unmodified tissue in vitro.
An in vivo model of an infected, third-degree burn also was used to assess the bacteria-fighting ability of Stratatech’s genetically-engineered tissue. The study showed that the modified tissue reduced the growth of A. baumannii by 100-fold compared to unmodified tissue. The unmodified tissue contained a bacterial level that exceeded the criteria for clinical infection. A. baumannii is a pathogenic, multi-drug-resistant bacterium responsible for an increasing number of virulent hospital-acquired infections.
The antibiotic resistance of A. baumannii and other bacteria is a major challenge in the treatment of burns and other skin injuries, not just in the United States, but around the world. Bacterial infection is a major obstacle to wound healing and the primary reason for short-term skin graft failure. In addition, nosocomial infections add significantly to the hospital costs of burn and other skin injury patients. A 2004 U.S. study found that burn patients infected with A. baumannii had average hospital costs of nearly $100,000 more than uninfected patients with similar burns. (Am J Infect Control. 2004 Oct;32(6):342-4.)
The anti-infective capacity of Stratatech’s genetically-engineered tissue, which is being developed and commercialized by the company as ExpressGraft Enhance skin substitute through a worldwide exclusive license from the Wisconsin Alumni Research Foundation, or WARF, is produced by genetically engineering the elevated expression of a naturally-occurring antimicrobial host defense peptide called hCAP-18/LL-37. hCAP-18/LL-37 was selected because of its broad antimicrobial activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant S. aureus (MRSA), vancomycin-resistant E. faecalis (VRE) and other antibiotic-resistant hospital-acquired infections, as well as some fungi and viruses. The enhanced tissue possesses a full-thickness structure and barrier function similar to that of native human skin. The cell type used to generate the ExpressGraft tissue has been demonstrated to be non-tumor-producing and free from detectable pathogens, characteristics critical for cell-based, regenerative medicine therapies for patient use.
“Bacterial infection is a substantial cause of skin graft rejection and additional health care costs,” said Lynn Allen-Hoffmann, Ph.D., Stratatech’s founder, chief scientific officer and chief executive. “The potent anti-infective capability Stratatech has engineered in our living human skin substitute can be an important tool in improving skin-injury patient outcomes, and reducing the incidence and expense of hospital-acquired infections. We look forward to beginning the clinical evaluation of our antimicrobial skin substitute in the near term.”
The company’s work on the genetically-engineered living human skin substitute was funded in part by a Small Business Innovative Research (SBIR) grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) to Stratatech Corp. (R44DK069924-05).
About Stratatech Corp. and StrataGraft skin substitute tissue
Stratatech Corp. is a Madison, Wis.-based a regenerative medicine company focused on the development and commercialization of cell-based, tissue-engineered therapeutic skin substitute products. The company’s valuable product pipeline, based on its patented NIKS human keratinocytes, is comprised of the next generation of skin substitute products that have numerous advantages over tissue-engineered products generated from human skin sourced by conventional means.
Stratatech’s StrataGraft tissue is a second-generation human skin substitute that exhibits normal human skin structure and function. It is manufactured using the company’s proprietary NIKS® human keratinocytes, which were discovered at the University of Wisconsin. Keratinocytes are the cells that make up approximately 90 percent of the epidermis, the outer layer of human skin. NIKS cells are a consistent source of pathogen-free, non-tumor-producing, long-lived adult progenitor cells. These cells faithfully reproduce normal human skin tissue architecture and barrier function when cultured appropriately.